Research targets pest of rice and sugarcane

Jay Cockrell | Nov 12, 2004

The Mexican rice borer, a serious pest of rice and sugarcane, is rapidly moving east through the Texas Rice Belt toward Louisiana’s high-dollar sugarcane industry.

Migrating up from Mexico, the Mexican rice borer was first discovered in Rio Grande Valley sugarcane in 1980. It quickly became a devastating pest, causing some farmers to forego harvesting entire fields. Over the next two decades, the insect gradually moved northeast and during the 1990s, it became a serious threat to rice.

Mo Way at the Texas A&M University System Agricultural Research and Extension Center in Beaumont, and Gene Reagan with the Louisiana State University Ag Center, have teamed up to help farmers in both states combat this pest. The collaborative research project began in 2000. According to Way, only a portion of the work has involved insecticides.

“The main research focus has been toward development of cultural and production practices, together with varietal resistance, to reduce pest problems with the Mexican rice borer,” Way said. Another factor, which emphasizes integrated pest management, balances the use of diverse control tactics. “If any single control tactic can be reduced, the selection pressure on the pest population is also reduced,” explained Way, “and this enhances the long-term success in controlling the pest.”

This system often includes biological controls to conserve beneficial insects, such as predators and parasites, which frequently contain pest populations below damaging levels. The researchers also are seeking to develop a Mexican rice borer- resistant variety that would be less attractive to the adult female for egg-laying.

Researchers at the Texas A&M University System Research and Extension Center in Weslaco are conducting greenhouse studies to determine the insect’s egg-laying preferences in certain varieties of rice and sugarcane.

Varieties of rice have been tested in the field to assess differences in stem borer resistance with respect to planting dates. Early research indicates that modifying the planting date may lessen the insect’s impact. The initial emphasis of collaborative studies on the Mexican rice borer was to determine the pest movement through Texas rice acres. In 2000, yield losses of more than 50 percent in treated and untreated experimental plots in Ganado underscored the seriousness of the problem.

With the help of Extension agents, farmers and the Texas Department of Agriculture, researchers have recorded insect movement into several Texas counties. For example, in Galveston County, 2,069 insects were collected in 2002, and 3,755 in 2003.

“Even though our trapping did not reveal any newly-infested counties in 2003, the increases in numbers can be interpreted as a signal that the pest continues to build populations and spread into new areas,” Way said.

As the Mexican rice borer spreads into new areas and new cropping systems, multi-state interdisciplinary collaborative work will become more important. Since its inception in 2000, the collaborative effort between Way and Reagan has brought in more than $500,000 in national funding through the U.S. Department of Agriculture Cooperative State Research, Education and Extension Service.

“This stem borer respects neither commodity nor political boundaries,” Way said, “and successful management of the pest must emphasize an area-wide approach. To provide the greatest benefit to our producers, we want to develop and implement practices that not only protect the host crops, but also reduce pest populations throughout the region.”